FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_trap.c
1 /*-
2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * the University of Utah, and William Jolitz.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
38 */
39
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: releng/5.3/sys/kern/subr_trap.c 136588 2004-10-16 08:43:07Z cvs2svn $");
42
43 #include "opt_ktrace.h"
44 #include "opt_mac.h"
45 #ifdef __i386__
46 #include "opt_npx.h"
47 #endif
48
49 #include <sys/param.h>
50 #include <sys/bus.h>
51 #include <sys/kernel.h>
52 #include <sys/lock.h>
53 #include <sys/mac.h>
54 #include <sys/mutex.h>
55 #include <sys/proc.h>
56 #include <sys/ktr.h>
57 #include <sys/resourcevar.h>
58 #include <sys/sched.h>
59 #include <sys/signalvar.h>
60 #include <sys/systm.h>
61 #include <sys/vmmeter.h>
62 #ifdef KTRACE
63 #include <sys/uio.h>
64 #include <sys/ktrace.h>
65 #endif
66
67 #include <machine/cpu.h>
68 #include <machine/pcb.h>
69
70 /*
71 * Define the code needed before returning to user mode, for
72 * trap and syscall.
73 *
74 * MPSAFE
75 */
76 void
77 userret(td, frame, oticks)
78 struct thread *td;
79 struct trapframe *frame;
80 u_int oticks;
81 {
82 struct proc *p = td->td_proc;
83
84 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
85 p->p_comm);
86 #ifdef DIAGNOSTIC
87 /* Check that we called signotify() enough. */
88 PROC_LOCK(p);
89 mtx_lock_spin(&sched_lock);
90 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
91 (td->td_flags & TDF_ASTPENDING) == 0))
92 printf("failed to set signal flags properly for ast()\n");
93 mtx_unlock_spin(&sched_lock);
94 PROC_UNLOCK(p);
95 #endif
96
97 /*
98 * Let the scheduler adjust our priority etc.
99 */
100 sched_userret(td);
101
102 /*
103 * We need to check to see if we have to exit or wait due to a
104 * single threading requirement or some other STOP condition.
105 * Don't bother doing all the work if the stop bits are not set
106 * at this time.. If we miss it, we miss it.. no big deal.
107 */
108 if (P_SHOULDSTOP(p)) {
109 PROC_LOCK(p);
110 thread_suspend_check(0); /* Can suspend or kill */
111 PROC_UNLOCK(p);
112 }
113
114 /*
115 * Do special thread processing, e.g. upcall tweaking and such.
116 */
117 if (p->p_flag & P_SA)
118 thread_userret(td, frame);
119
120 /*
121 * Charge system time if profiling.
122 */
123 if (p->p_flag & P_PROFIL) {
124 quad_t ticks;
125
126 mtx_lock_spin(&sched_lock);
127 ticks = td->td_sticks - oticks;
128 mtx_unlock_spin(&sched_lock);
129 addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio);
130 }
131 }
132
133 /*
134 * Process an asynchronous software trap.
135 * This is relatively easy.
136 * This function will return with preemption disabled.
137 */
138 void
139 ast(struct trapframe *framep)
140 {
141 struct thread *td;
142 struct proc *p;
143 struct ksegrp *kg;
144 struct rlimit rlim;
145 u_int sticks;
146 int sflag;
147 int flags;
148 int sig;
149 #if defined(DEV_NPX) && !defined(SMP)
150 int ucode;
151 #endif
152
153 td = curthread;
154 p = td->td_proc;
155 kg = td->td_ksegrp;
156
157 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
158 p->p_comm);
159 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
160 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
161 mtx_assert(&Giant, MA_NOTOWNED);
162 mtx_assert(&sched_lock, MA_NOTOWNED);
163 td->td_frame = framep;
164
165 if ((p->p_flag & P_SA) && (td->td_mailbox == NULL))
166 thread_user_enter(td);
167 /*
168 * This updates the p_sflag's for the checks below in one
169 * "atomic" operation with turning off the astpending flag.
170 * If another AST is triggered while we are handling the
171 * AST's saved in sflag, the astpending flag will be set and
172 * ast() will be called again.
173 */
174 mtx_lock_spin(&sched_lock);
175 sticks = td->td_sticks;
176 flags = td->td_flags;
177 sflag = p->p_sflag;
178 p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU);
179 #ifdef MAC
180 p->p_sflag &= ~PS_MACPEND;
181 #endif
182 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK |
183 TDF_NEEDRESCHED | TDF_INTERRUPT);
184 cnt.v_soft++;
185 mtx_unlock_spin(&sched_lock);
186 /*
187 * XXXKSE While the fact that we owe a user profiling
188 * tick is stored per KSE in this code, the statistics
189 * themselves are still stored per process.
190 * This should probably change, by which I mean that
191 * possibly the location of both might change.
192 */
193
194 if (td->td_ucred != p->p_ucred)
195 cred_update_thread(td);
196 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
197 addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
198 td->td_profil_ticks = 0;
199 td->td_pflags &= ~TDP_OWEUPC;
200 }
201 if (sflag & PS_ALRMPEND) {
202 PROC_LOCK(p);
203 psignal(p, SIGVTALRM);
204 PROC_UNLOCK(p);
205 }
206 #if defined(DEV_NPX) && !defined(SMP)
207 if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
208 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
209 PCB_NPXTRAP);
210 ucode = npxtrap();
211 if (ucode != -1) {
212 trapsignal(td, SIGFPE, ucode);
213 }
214 }
215 #endif
216 if (sflag & PS_PROFPEND) {
217 PROC_LOCK(p);
218 psignal(p, SIGPROF);
219 PROC_UNLOCK(p);
220 }
221 if (sflag & PS_XCPU) {
222 PROC_LOCK(p);
223 lim_rlimit(p, RLIMIT_CPU, &rlim);
224 mtx_lock_spin(&sched_lock);
225 if (p->p_runtime.sec >= rlim.rlim_max) {
226 mtx_unlock_spin(&sched_lock);
227 killproc(p, "exceeded maximum CPU limit");
228 } else {
229 if (p->p_cpulimit < rlim.rlim_max)
230 p->p_cpulimit += 5;
231 mtx_unlock_spin(&sched_lock);
232 psignal(p, SIGXCPU);
233 }
234 PROC_UNLOCK(p);
235 }
236 #ifdef MAC
237 if (sflag & PS_MACPEND)
238 mac_thread_userret(td);
239 #endif
240 if (flags & TDF_NEEDRESCHED) {
241 #ifdef KTRACE
242 if (KTRPOINT(td, KTR_CSW))
243 ktrcsw(1, 1);
244 #endif
245 mtx_lock_spin(&sched_lock);
246 sched_prio(td, kg->kg_user_pri);
247 mi_switch(SW_INVOL, NULL);
248 mtx_unlock_spin(&sched_lock);
249 #ifdef KTRACE
250 if (KTRPOINT(td, KTR_CSW))
251 ktrcsw(0, 1);
252 #endif
253 }
254 if (flags & TDF_NEEDSIGCHK) {
255 PROC_LOCK(p);
256 mtx_lock(&p->p_sigacts->ps_mtx);
257 while ((sig = cursig(td)) != 0)
258 postsig(sig);
259 mtx_unlock(&p->p_sigacts->ps_mtx);
260 PROC_UNLOCK(p);
261 }
262
263 userret(td, framep, sticks);
264 mtx_assert(&Giant, MA_NOTOWNED);
265 }
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